Table 4.4 on p. 127 in the following book A. V. Shenoy and D. R. Saini, Thermoplastic Melt Rheology and Processing, Marcel Dekker Inc., New York (1996), lists flow activation energies, processing temperature ranges and Tg + 100 values for a number of common polymers (LDPE, HDPE, LLDPE, PP, PS, Cellulosics, Acrylics, Nylons, PET, PBT, PC, PVDF, PPO, PPS, PES, PEEK, PEI, PAr). Based on those values you should be able to pick the thermoplastic polymer that would suit your needs.
The other book where you may get some useful information would be
Charles P. MacDermott and Aroon V. Shenoy, Selecting Thermoplastics for Engineering Applications, Marcel Dekker Inc., New York (1997).
Selecting the best thermoplastic resin is made easier by the guidelines presented in this book. Included are methods of ranking the thermoplastics by their properties, price, and processability, along with quick-reference tables of rankings.
Besides PPO, PPS, PEEK, the other thermoplastic polymers which have higher melting points are PEI and PAr. All these thermoplastics are often termed as specialty polymers and you could browse through the following paper to get an idea about them and their rheological characteristics.
D. R. Saini and A. V. Shenoy, Melt rheology of some specialty polymers, J. Elastomers Plastics, Vol. 17, pp. 189 -217 (1985).
I don´t know what is reasonably high melting thermoplastic (I asume in temperature). More over you need something flexible, as you posted. Let me sugget one multiarm SBS Solprene 9618 and SEBS 6174, which are higher Mw elastomers, if you need high flexible materials. If flexible property is not so relevant Stanyl grades (polyamides) are slightly flexible material used in tribological applications. Otherwise PEEK is the option...