I think 50 is reasonable for a UT, though making it 75 would not be much of a stretch either. At $100 donor rank you get to add enhanced titles up to 230 characters which includes your HTML coding.
My initial code was 230 and it worked fine since I tested it, but it seems an admin had to edit it differently, to maybe help the site in some way, and made it longer. There is im sure back end issues which is why these restrictions exist. If it is possible and increasing these limits wouldnt affect the site, then I would maybe increase the character limit for $100 donors+ as richard and matthew want new perks anyway.