I have just killed a tube because my main source of air is a (large-ish) mini pump. it failed during pumping right around the valve stem base probably from me not being able to keep the head of the pump still enough while pumping.

Does a presta 'jumper' exist?

I'm just looking for something to act as a bit of an intermediary of about 8" of hose between the bike and the pump. I do have a floor pump, but only at 1 of the 3 possible locations by bike could sit for an extended period of time, so there's a 2/3 shot I'm using a hand pump. It doesn't need to be fancy, and I'm willing to over-inflate since I carry a gauge with me to reach proper pressure after pumping. Maybe something that threads onto the presta valve and is a gutted presta on the other side for the pump to grab?