Ettus Research USRP B200 / B210 should be a good candidate too. Although the FPGA is kind of old (Spartan 6), and the cost is on the high side. AD936X Frontend
Limemicro LimeSDR [Mini] should fit your requirement too. It has Altera FPGA and Limemicro LMS7002M RF Frontend.
Both systems published enough documents so you can use them as FPGA + RF Frontend Dev Board easily.