I hate when this happens. 
The Parallax SX microcontroller line has reached production EOL. The owner of the SX design
(www.ubicom.com) has given Parallax final notice that we are to place a lifetime buy of wafers. We
recognize this announcement will be difficult for customers who have designed the SX into their products.
We share your disappointment.
http://www.parallax.com/Portals/0/Downloads/docs/prod/sx/SX_EOL_Notice.pdf
So the question is, do I
1> Do nothing. I have a couple spares in case something shit the bed.
2> Switch to another uC?
3> Switch to a soft uC like Picoblaze and run it on fpga?
4> Switch to a soft MP like Microblaze and run it on fpga?
There are pros and cons to each of the solutions.