>So upon reflection, I thought what I might do is hybridize the
>two—sort of hang the details I remember from the Elder Days on the
>framework of the HBS BattleTech's premise and see what happens.

I say, go for it! For one thing, I'm betting your old campaign didn't have all of the non-combat positions fully staffed by players, so you'd be adding new characters to the story anyway.

Also, in re:

>and the rules themselves were... well, with the best will in the
>world, a bit half-baked.

They didn't get much better from my experience. Or at least, Mechwarrior Third Edition was a massive plonker. For starters, they did away with the parity between MW skill ratings and Battletech skills, which meant that you now needed to use a conversion chart to figure out where you were in your 'mech.

Even worse though was the combination of Battletech-esque combat rules, which meant you had a to-hit roll of about 8 on 2d10+skill to shoot someone unless they were running for their life, with a very realistic wounding chart that included the phrase "the character gains the Addiction (2) Negative Trait, representing anti-rejection drugs he/she will be required to take for the rest of his/her career or die" far too often for a campaign to last very long.

"This is probably a stupid question, but . . ."