I've usually got a tokina 28-70mm on my lens. Of course, I hit the same problem at 70 on the full frame that you hit at 50. It's one of the reasons i'm looking at the 24-105mm f/4L IS at some point (even though there's also the 24-70mm f/2.8L - that 70mm is tight). That's what I was renting at the wedding on saturday. It's a really nice lens to play with. (Check out ziplens.com or rentglass.com - cheap, netflix-ish style lens rentals : )

Your quantary sounds like it's roughly about the same as my current 75-300mm in terms of issues : )

Alas, while the 105mm had a bit longer reach (though, being roughly equivalent to 65mm on your body - not -that- much longer : ) the bodies and heads in front of me blocked a lot of the ceremony shots for me - and I was a bit shyer about standing up to shoot during the ceremony proper.