Is the 55cm for the seat tube just the tube or the overall seat height??? My approach would be to go with the largest frame that will still give you a total saddle height (seat tube and seat post length) and adjust the seat post to get the right saddle height. Then adjust the size of the stem to give a longer reach to the bars. I ride a 62 and a 58 in the same model and have been able to make both work just fine by playing with the seat post height and stem lengths.

That does seem like a large difference between the seat tube and top tube though. Sounds like short legs with extremely long upper torso and arms????