Well. Where to start?
There are 21 regional German football associations. So each of them has its own regional cup. Only teams from level 3 and lower are allowed to participate in these regional cups (and the reserves from Bundesliga and 2. Bundesliga teams tend to don't participate at these cups anymore as they are already qualified for the first round; and nearly all cups have permitted the participation of reserve teams by now, but there are exceptions, see below). So you'll have to check what team belongs to what region.
I would say that is is a lot of effort to simulate these cups. You would have to create loads of leages and teams only to fill the gap for the first rounds. And you have to manage somehow the distribution to the 21 regions. Karlsruhe for example participates in the Badischer Pokal and Heidenheim participates in the Württemberg Cup. But both teams would play at the same level 4 (Regionalliga Südwest) and 5 (Oberliga Baden-Württemberg). So you need (!) to create level 6 and you would have to set these levels for every team from Bundesliga down to level 6 first, to direct the teams to the right cup via these level 6 divisions:
1 Verbandsliga Schleswig-Holstein Nord-West -> Schleswig-Holstein-Cup
2 Verbandsliga Schleswig-Holstein Nord-Ost -> Schleswig-Holstein-Cup
3 Verbandsliga Schleswig-Holstein Süd-West -> Schleswig-Holstein-Cup
4 Verbandsliga Schleswig-Holstein Süd-Ost -> Schleswig-Holstein-Cup5 Landesliga Hamburg Hammonia -> Hamburg Cup
6 Landesliga Hamburg Hansa -> Hamburg Cup -> Hamburg Cup7 Landesliga Bremen -> Bremen Cup8 Landesliga Weser-Ems -> Niedersachsen Cup
9 Landesliga Hannover -> Niedersachsen Cup
10 Landesliga Lüneburg -> Niedersachsen Cup
11 Landesliga Braunschweig -> Niedersachsen Cup12 Verbandsliga Mecklenburg-Vorpommern -> Mecklenburg-Vorpommern Cup
13 Verbandsliga Brandenburg -> Brandenburg Cup
14 Verbandsliga Berlin -> Berlin Cup15 Verbandsliga Sachsen-Anhalt -> Sachsen-Anhalt Cup
16 Verbandsliga Sachsen -> Sachsen Cup
17 Verbandsliga Thüringen -> Thüringen Cup18 Verbandsliga Westfalen I -> Westfalen Cup
19 Verbandsliga Westfalen II -> Westfalen Cup20 Landesliga Niederrhein Gruppe 1 -> Niederrhein Cup
21 Landesliga Niederrhein Gruppe 2 -> Niederrhein Cup
22 Landesliga Niederrhein Gruppe 3 -> Niederrhein Cup23 Landesliga Mittelrhein Staffel 1 -> Mittelrhein Cup
24 Landesliga Mittelrhein Staffel 2 -> Mittelrhein Cup25 Verbandsliga Rheinland -> Rheinland Cup
26 Verbandsliga Südwest -> Südwest Cup (Pfalz)
27 Verbandsliga Saarland -> Saarland Cup28 Verbandsliga Hessen Nord -> Hessen Cup
29 Verbandsliga Hessen Mitte -> Hessen Cup
30 Verbandsliga Hessen Süd -> Hessen Cup31 Verbandsliga Nordbaden -> Baden Cup
32 Verbandsliga Südbaden -> Südbaden Cup
33 Verbandsliga Württemberg -> Württemberg Cup34 Landesliga Bayern Nordost -> Bayern Cup
35 Landesliga Bayern Nordwest -> Bayern Cup
36 Landesliga Bayern Mitte -> Bayern Cup
37 Landesliga Bayern Südost -> Bayern Cup
38 Landesliga Bayern Südwest -> Bayern Cup
1-11 are child divisions to Oberliga Bremen, Oberliga Schleswig-Holstein, Oberliga Hamburg and Oberliga Niedersachsen (level 5 each) -> these level 5 comps are child comps to German Regional Div. North (level 4) -> this level 4 comp is a child comp to 3. Liga (level 3)
12-17 are child divisions to Oberliga Nordost-Nord and Oberliga Nordost-Süd (level 5 each) -> these level 5 comps are child comps to German Regional Div. Northeast (level 4) -> this level 4 comp is a child comp to 3. Liga (level 3)
18-24 are child divisions to Oberliga Westfalen, Oberliga Niederrhein and Mittelrheinliga (level 5 each) -> these level 5 comps are child comps to German Regional Div. West (level 4) -> this level 4 comp is a child comp to 3. Liga (level 3)
25-33 are child divisions to Oberliga
SüdwestRheinland-Pfalz/Saar, Oberliga Baden-Württemberg and Hessenliga (level 5 each) -> these level 5 comps are child comps to German Regional Div. West (level 4) -> this level 4 comp is a child comp to 3. Liga (level 3)
34-38 are child divisions to Bayernliga North and Bayernliga South (level 5 each) -> these level 5 comps are child comps to German Regional Div. Bavaria (level 4) -> this level 4 comp is a child comp to 3. Liga (level 3)
To make it easier I would ban reserve teams from these Regional Cups although they are allowed to play within (see Stuttgarter Kickers II for example in this season:
http://ergebnisdienst.fussball.de/begegnungen/bitburger-wfv-pokal-gruppe-2/wuerttemberg/wfv-verbandspokale/herren/spieljahr1213/wuerttemberg/M35S1213Wk53506). But still you need to create all (!) Landesligen and all teams (!) within. And after that you have to create 21 single regional cups. And if this isn't enough: Besides the 21 cup winners there are 3 more teams that are allowed to participate: one representant of Bavaria (the 2 losers of the semi-finals play against each other, the winner plays against the runner-up of the Regional cup and this winning qualifies for DFB Pokal), Niedersachsen (the runner-up in the Regional cup) and Westfalen (the runner-up in the Regional cup).
So you see. Crazy.