I've compiled and am running tin (=tin-1.6.2) on sparc. I had it load several newsgroups, containing up to 100,000 articles, and it didn't appear to choke or crash. Posting to misc.test works as well.
That should be net-news/tin. Sorry. :)
I use tin all the time; just not this version. Let me check it out, then I'll do it.
Done. It's ~sparc in cvs, and it still works for me.