It would be relatively easy to make an ARM2 equivalent indeed. With a modern process it would be as fast as an ARM7. Of course without Thumb it would it would need 50% more flash, so ARM7 has the area advantage. Then there is Cortex-M3...
A StrongARM equivalent would be a lot more interesting, but it has to avoid the more recent MMU and cache patents. Even so, a
64MByte address space is pretty limiting for a $100 laptop...Also it's not obvious to me that designing your own ARM would be cheaper than licensing (the development cost of a core is spread over many licensees). It only makes sense for very high volumes as you avoid the royalties. I don't rule it out entirely - I can see it done as a free FPGA core for example.
Wilco