I have a number of 4-track tapes recorded at 9.5 cm/sec... I can only record them to my pc at 4.75 cm/sec with the effect of being twice as long as recorded and at half pitch and the added interest of tracks 3&4 being recorded backwards.
Sample programs are fine at simple 'reverse' to switch tracks 3&4 around, however the re-pitch and time stretch functions in most sample programs work independently of one another and don't appear especially accurate in their results.
Are there any dedicated sample fixes available or other possible work arounds?
A typical 4 track audio tape will contain 4 discrete channel tracks, L+R stereo recorded in the "A" direction and L+R stereo recorded in the "B" direction. Every audio editor I have experimented with will allow time and pitch compression (together or separately) to return to the original signal with absolute accuracy. I suggest you try various trial software until you find a program which suits you best.
If this makes your head hurt, check craigslist and ebay for a cheap player capable of 3.75in/sec or 9.5 cm/sec playback.