Well, to actualy talk about the Stooping Hawk for a moment... If the terrain were right and for some reason I just had to take one against some monster of an assualt mech, there are other intresting choices.
In open terrain, especaly against the Hellstar, I'm looking at the C. Yes, its only got a two hex edge, and you need the theroetical infinate map to work it, but its as good a stratigy as any other against that monstrosity. The C's got a monster BV, so this doesn't really exploit that (its only about 360 less than the Supernova, which matchs its range, so its not as good a choice for that)
With a piloting advantage, you can almost do that with the A against the Supernova. Twin PPCs vs quad (usable) ER LLs gives up some power, but if you're hitting more often, both due to your movement edge and the pilot your (less than you'd think) lower BV gets you, its not impossible. I'd definaly be prepaired to try it, even if I didn't like my odds (I almost took a Night Gyr Prime with one once, taking a 2/3 against a 3/4 for skills).
Another I might take is the D. It's ground bound, so you need terrain to close, but not so rough that you can't keep up with the 3/5/3 assualt you're fighting. But, its huge array of heatsinks give it throw weight above the problematicly dissapated Supernova and in the ballpark of the monstrous Hellstar. And, with BV the better part of a thousand points below the large laser machine and just about 60% of Mr PPC's, you really can exploit that in terms of pilot skills or supporting forces (how about a Chaeronea to help even things out? or a Huitzilopochtli? BVs on both look like they fit for the Hellstar fight).
If I'm doing the BV thing, I just might try the even cheaper E. The ATM ER rounds can snipe, and the LB can throw a bunch of dice rolls out there to hope for the golden BB...
Not ideal in any case, but hardly worse than a Stormcrow or Hunstman (the Periah/Septicemia has some nice modern veriants I like, so I might take it if I could in this fight).