I don't think I have ever blended lager yeasts with ale yeasts, but I have often blended yeasts when targeting specific combinations of characteristics. My best beers I've made are almost always from yeast blends. (And less frequently, some of my worst beers too, TBH.)
I've taken some blends out to 5-7 generations, with reasonable consistency. Some drift quickly, but some stay pretty close to the original blend. I usually try to match reproductive speed & lag for that reason.
Do it! Best case scenario: your best beer ever. Worst case scenario: probably still a drinkable beer.