you can imagine my surprise when i was editing a text file and found that i couldn't find a way to have UE do red underlining of misspelled words in a text file.

that really sucks - i'm very much missing this feature

That would be a cool feature.  Don't hold your breath, though.

No need to hold your breath.  Ultra-Edit 13 is here with: spellcheck-while-you-type capability, red underscored misspellings, improved regex support in find/replace, improved hex mode that reflects true unicode encodings (prior versions of UE displayed UTF-8 files as UTF-16 in hex mode which was really confusing...Hex mode showed a UTF-16 BOM and two-byte characters when the actual file on the hard disk had a UTF-8 BOM and single-byte characters).

it has some unique fantastic features like 3-way comparison, and has an excellent in-place editor which blows beyond compare away in terms of being able to do serious edits while comparing

Not for long...  When Beyond Compare 3 Professional is released, it's 3-way merge and in-place editing will close the gap.  I've tried Araxis Merge.  It doesn't stand a chance...  ;)