Not to my knowledge.
Izuho had some commentary on
PHANTASY STAR 1st Series Complete Album:
booklet page 6. I'm not really sure that that contains any useful information beyond the Phantasy Star works, though, aside from confirmation that Takeuchi is the maiden name and Numata (沼田) is the married name.
Izuho Numata is credited for sound for 幻世快進劇 (I believe that's read Gensei Kaishingeki, but I can't make out the reading here too well:
http://www.amazon.co.jp/dp/B00005OI9J), a game included in BOOK edition #12 of Compile's Disc Station series of disc-based magazines and later released on its own. That was first released in September 1996, which would've been after Ippo joined Capcom in what, 1994?
So anyway I'm still not convinced they're the same person, but direct confirmation would be fantastic.