There are some complexities in chip supply and manufacturing that come into play when we deal with new product engineering and production that preclude me from being able to specify things like lead times.
I voted for the xM1 + T5577 because it would mean the entire chip would be re-programmable… a true “hacker’s chip”… but there are complexity issues here as mentioned above that would make this particular arrangement slightly more difficult to create… though I think I will explore it.