Ugh, YAPBWRH. (Yet Another Pokemon Black and White ROM Hack)
How about doing something original and grabbing that ALPHA 4th and 5th gen Map editor and editing some maps? Maybe figure out where map banks are stored in the ROM and add a new area or two? Or how about "unlocking" access to Liberty Island and the Musical Cave?
I don't mean to troll you or anything like that, It just seems that there are WAAAY to many "Able to catch em' all" Pokemon ROM hacks of Black and White with edits movesets, stats, evolutions, trainers, and DERP-HARD difficulty curve.
I will make a Pokemon Grey when the proper tools are made available. [Provided that Nintendo doesn't beat me to it!]
Here are a list of others (That I can think of)
Pitch Black and Pure White
Blaze Black and Volt White
Dark Ruby and Light Sapphire [Not what you're thinking of, it is not a 3rd gen Remake.]