I'm in a similar boat as you with my winter basement temps. I used WY2007 last year in the mid 50's ambient for a hoppy helles that was quite clean. Could be mind over matter, but I definitely picked up a Bud-like flavor in the finish. Otherwise it was almost too clean for how I like my lagers. I've also heard 2124 works suitably for lagers at higher temps. I've heard the same about 34/70 and I plan on giving that a try myself this winter.
I think the main reason I've had success with lagers even with less-than-optimal temperature control is pitching as low as I can manage. I shoot for 45F for a pitching temp whenever possible. I don't brew a lot of lagers, but I find that the lager yeasts I've worked with can be pretty forgiving of warmer temps as long as you let them start off as cold as you can manage.