IBM & TI can also bring a microprocessor to market, and have pretty extensive experience with x86. To be fair, their last stand-alone x86 were i486 contemporaries, but it's not as though they don't understand the innovations that lead from i486 to i7 (see: Power7). If there was a market demand, either could probably produce an x86 compatible, depending on licensing issues. If you go back to 8086 and i286 then NEC & Fujitsu made x86 chips and still have formidable chip design capabilities.