I would love nothing more for this title to be released on DS.
At first I thought it might be a good chance to break into the Japanese market, however thats not really likely.
(Im not sure how happy the devs are with these constant comparisons but I dont think they will shout at us for it) See certainly Aquaria is an original game but definetly has similarities to that of the original Metal Gear, Metroid, Castlevania: Symphony of the Night etc.
ie You control a character traversing various environments progressively gaining more abilities to allow you to progress even further. But thats great, its the forumla that made those other games great. However for some damn stupid reason these games dont do very well in Japan!
Its really weird! Perhaps a redesign of the character to be more Anime style would give it more market appeal for a Japanese version. Its is a good idea, if you get a hit on the NDS can you imagine the profits?
I wouldnt concern yourself with the PSP too much with its current sales (although it is picking up). The NDS really should be your priority especially with the more general versus hardcore demographic of each platforms audience (plus dont forget the global sales of the NDS).
For consoles. To appeal to Japanese markests there is no point using the XBLA, since the 360 will never succeed there. However in North America is the ideal platform. With current downloads of PS3 titles being far more popular in Europe combined with the knowledge that the style of game you made appeals to them greatly (even more so than North America) it would be hard to ignore the PS3 either.
IMO I would recommend you release an online version for both XBLA and PS3 if possible! (But I imagine they tend to have exclusive contracts - I would look at your current sales to determine which platform you should release it on) and then attempt to redesign the game slightly for a Japanese audience on the NDS. With a later released for Western Countries.
If you haven't got much experience with the NDS or Japanese market in general, then I recommend you guys outsource if you have enough cash flow or investors. (Seems like you guys dont have much time as it is!).
If your going to outsource for DS development here are some suggestions;
Nex Entertainment, Marvelous Interactive, TOSE, Paon Corporation, Altron, Backbone Entertainment, Sumo Digital,.
No idea on pricing though.
Good luck!