had an idea that should have occurred to me long ago
a place I used to work, we used to set up permanent site-to-site VPN tunnels between offices all over the world. and it worked really well. this was with business class switch/router hardware of course.
but routers with ddrwt/openwrt/tomato/etc. are now capable of a lot of the same functions - between/amongst each other, mostly (plus in my experience, tunnels behave better if you have the exact same device on each end anyway). and support all sorts of common flavors - l2tp/ipsec, pptp, openvpn...
I have never tried any of the paid public/popular VPN host services, so I don't know if they only support direct VPN clients from single devices, or if they support site-to-site tunnels too. I imagine if some did, they would advertise so on their website.
if tunnel connection is supported by providers, that might be a workaround. (possible annoyance: all traffic from behind your router would also be on VPN, unless maybe some fancy routing glue code is applied)
another way is if someone in UK has ddwrt router and has a friend in US with ddwrt router, you could totally set up site-to-site -- this is existing functionality. of course there still probably needs routing glue on both ends (mainly, knowing most/all of the amazon services IPs used by firetv apps)
probably too much time/work/testing, but...