These rumors of the R400 coming late q4 2003 or even 2004 sound like nVidia fans attempting to cause some ruckas against ATI.
The rumors are widespread, as even the ATi fanboy favorite tabloid (the Inquirer) has hinted at such delays. Notice how R400 hasn't even been mentioned at CeBit or the GDC? Every industry analyst and web-presence has redrawn their roadmaps comparing R400 to NV40 rather than NV35.
I'm not sure how much ATi puts into R&D (I'm too lazy to pull their filings

), but considering the R300 was their first truly stellar core, it makes you wonder if they would be able to pull off such a feat consecutively. nVidia invented the 6 month product cycle, so their track record is proven. Considering they already have Xeon server clusters running NV50 simulations and compilations, there's no doubt NV40 is well into development already. Being the market leader (with considerable cash reserves and capital) affords such luxuries.
Or maybe it would be best to take it from the horse's mouth; Orton in his last shareholder's meeting announced the 9800pro as well as the RV350 parts. He boldly claimed that R350,
NOT R400 would retain the performance crown for ATi through
the end of the calender year. I guess he didn't seem to feel as confidently as you do about a FY'03 release of R400, but then again, I'm sure he didn't think NV35 would be released so soon after NV30.
Chiz