We bought some for the whole family from c-wear in Australia a few years ago. They were 100+ SPF before they changed the SPF guidelines - now they're 50+ but it's the same coverage.
I love mine - it's long sleeved, and actually keeps me cooler in the hot sun once it's wet! They do dry, but not as quickly as a bathing suit alone - which is a good thing, in my opinion! They're also good when it's chilly but sunny and you still want to be on the beach but not swim - they block the sun, but can help keep you warmer too without feeling like you're over-dressed.
C-wear has a lot of options as well - they're a little more expensive than, say, Land's End, but they're high quality, and apparently very popular in Australia where the sun's a lot hotter than in the US. At my last physical, my doctor actually commented on how healthy my skin was, and I mentioned them to her, and ended up giving her the URL so she could get some for her kids!
There are rashguard options available at a lot of places - we need to replace my DDs as she's finally outgrown her shirt and we're debating C-wear again or just going with Land's End - but I wouldn't dream of swimming outside without one now.
Amanda