the best fighter i've ever seen (on foot, that is) was a guy who would run around. he was scary b/c you always had to watch him, no matter where you were on the field. granted, power is a little more important in ship combat than it is in human combat, but speed is still much more dangerous than power (i.e. destroyer vs frigate, reb cruiser vs fed cruiser). i'm definitely much more a corvette person than a kestrel person (of course, my opinion might change if i could offload the lightning bay i don't use and get a buttload of extra space; it's not like the kestrel's a slug)
as to the original question: like people have been saying, just keep trying. early on in my time with ev (like, back before i knew the strengths and weaknesses of all the ships and was still scared when i saw a fed cruiser), i captured a fed cruiser in some little civvie ship (either an argosy or a corvette). of course, with shields down, and not having been smart enough to off the rest of my enemies before departing my functional ship, i was cut down in seconds ("holy crap! i can't even outrun the torpedoes!"), but the point is that any ship which can successfully board a fed cruiser can board a kestrel
------------------
if you find yourself in bed with a raving lunatic, don't worry: looks can be deceiving, it's probably not me