I saw this via
Animenation.comApparently
Geneon is selling (quite!

) cheaper Region 1 NTSC DVDs of the OVAs.
This is good news for those people that didn't get (or afford

) the OVA special edition box.
For what I can tell OVA1 comes in 2 volumes and OVA2 in one volume (just like the OVA special edition box). However it seems that they are sold separately only (they may release a bundle...?).
The
Geneon's official page for the 1st vol. of OVA1 doesn't describe any special features..., apart from the 5.1 Japanese audio. :-/
[EDIT]:
Geneon's official page for the 2nd vol. of OVA1 says that this DVD will have the following extra features:
- Line Art
- Non-Credit Opening & Ending
- DVD Credits
It's not much, but... better than nothing

[/EDIT]
I didn't find a picture of the OVA2 DVD, but here are the others:


As you can see, no big difference on the covers (same usual Hanken Cels used in a different disposition).
However I'd like to see if the OVA2 cover surprises me, like the one found by
Nepotism Chainsaw 
(there aren't many Hanken Cels from OVA2 around).