What is the FPGA with the highest LEs / $?
This has been researched by UofT and Umass in the link below.
“ In between these extremes is a spectrum of logic block choices ranging from fine to coarse-grain logic blocks. FPGA architects over the last two decades have selected basic logic blocks made of transistors (noted above) [144], NAND gates [160], an interconnection of multiplexers [79], lookup tables [49], and PAL-style wide-input gates [217]. These choices were originally driven by intuitive insights on the part of architects, typically with very little data or analysis, with a few exceptions [79]. In this survey, we discuss how the research foundations for choosing a logic block were established, and then focus on the effect of logic block functionality on the three key metrics: area, speed, and power. In this discussion, we use silicon area as the proxy for cost, as is common. For a more detailed survey on the specifics of the logic blocks mentioned above, see [167] or [43].”
https://www.eecg.utoronto.ca/~jayar/pubs/kuon/foundtrend08.pdf