Long time across-the-pond lurker and all-round Lemons fan here - the genius this race breeds is fantastic!
I've have been following this thread with much anticipation and trepidation, now I have come to plead on behalf of my countrymen; do justice by this poor DB7 who has clearly been mistreated in its past life. If you have not had the opportunity to appreciate one in its proper condition, then I suggest you do so at the soonest available opportunity.
An Antrim Blue 2001 DB7 Vantage is a much loved member of my family (though not as long standing as the '71 TR6 PI) and as such I have had the opportunity to visit the DB7's birthplace at Newport Pagnell some months ago. I thought you folks might enjoy seeing where this future Lemon's life truly began:
I can confirm that the DB7 does indeed use the Jaguar IRS, and I believe it is a direct fit. If you need any parts I may be able to help source them, but I doubt you could get much at all in a Lemon's budget. IIRC a replacement wing mirror cost us £200 (~$300), not including the painted cover!