Femtocells/microcells aren't really an option (outside of Ting) unless you're paying full price for one f the big four carriers instead of an MVNO.
If you've got solid broadband, VoIP is always the cheapest option to go for home service... I've gone over plenty of quality providers at low prices with many various configurations over the years in the guide and elsewhere. The "internet connected landline replacements" are VoIP, most of them are just pre-packaged with an inflated price and lockout on any of the truly useful and fun features. Cheaper to roll your own, and really not that difficult. If you can fill out a web form and follow instructions (you registered to post here), you're golden.
I'm not a huge fan of GV, but it does have its uses if you can get past the Google privacy issues. Honestly, read the guide if you haven't already. You're a pretty creative lateral thinker, I'm sure you'll see how to implement a few of these things and work around the restriction.