My R7G remote controls my D504 and V880 so it's pretty safe to assume that the reverse holds true (that you can pretty much control any Pioneer LD player with almost any Pioneer player remote.) Just that if you get an American remote, you won't be able to adjust the comb filter or turn on the "D-EXT" feature (not that you really need to.)
I do wonder if you get a D704/79 or Elite 99 remote will you be able to adjust the comb filter as they have the controls to do so?
But if you REALLY want the actual R7G remote, I ordered one through Pioneer USA (after some back and forth email between them and Pioneer Japan) and the price was US$74 + S/H.
The part number is VXX2541.
You can apparently buy that through other means (like
this site) but it's not cheap!