Ting has a lot of support for bringing the Nexus 5 into the network. Surely any XDA-er should be able to activate an N5 (but only the one from Google Play, not from cell phone companies) with the help from on-line Ting support. Still some hurdles, but not enough that I'm not considering an N5 and giving up on my Windows Phone on T-Mobile (everyone keeps calling me in the holiday season and burning through my 100 minutes -- Skype okay to great outgoing, but no real viable incoming option on WP8 - incoming Skype via G-Voice to Skype number to T-Mobile number bad when driving and crashes when trying to answer sometiimes even with good wifi). Prior experience with Ting (Ting support is fantastic) and current experience with daughter's and wife's phone on Ting is very good, with the usual Sprint issues. Ting roams for voice which is important for upstate NY areas.
I have been using a Nexus 5 on Ting for a while now, works very nicely. Another thing I like about Ting is that it will roam on other CDMA carriers for voice and texting. I live in an area that is mainly CDMA so it works nicely for me.