drgondog
Major
If there are no escort fighters for the bombers, how about the A26 invader? You could put jet-assist take-off packs to get it up to altitude, then, with its 350 mph speed, 10 x .50 cal. mg's and 14 x 5 inch rockets it could mess with a few bombers.
It would do fine (as well as A-70) for middle altitude British bombers but would struugle to get to 25K against B-17s. Its service ceiling was 22K. Also, it won't do near 350 with a load. Last - it didn't make it to combat until mid 1944, by which time Allied fighters had the range to intercept over Germany.