I have not tried it myself but there are reports that you can (although with some effort) use a custom mobi/prc dictionary with Kindle for Android now (3.6.x versions):
EDIT: I have tried it and it works just fine for my older customized Dutch->English dictionary. The only drawback is that it has to be mapped to another language (Dutch is not in the menu). Not a clean solution but hey, it works!
Another possible solution would be Moon+Reader with Stardict/ColorDict. You would need to get rid of DRM of your mobi dictionaries and convert them to Stardict format. The conversion process would need a lot of work though - some custom scripts would be needed. (I have not tried this path)