Thanks everyone, it sounds like the AmFib tights are what I am looking for. My leg warmers, which stay up just fine as long as I put them on first and then put my shorts on, are fine for temps >40. I do have some knickers that can go over my leg warmers and shorts if I think the temps won't stay <37-38.

My regular shorts and bib-shorts are starting to show signs of wear/washing so much, and I would like to wear them next spring/early summer, so it is either get the AmFibs, or get another pair of shorts if I get tights w/out a chamois... This might be the most cost effective approach, but will look into it more before pulling the trigger. Temps aren't that low as of yet anyway.

My leg warmers fit me MUCH better this year. My weight is 50 pounds less than last winter - but my thighs are larger so no problem with them staying up