The FPGA based RISC-V hardware that I already have is much slower, has much less RAM and is in other ways more limited than QEMU. OTOH what's missing from QEMU is virtio support.

However none of this is relevant for Fedora builders, which must be 19" rackable server hardware. This is a non-negotiable condition from the Fedora project itself, and also quite understandable because they don't want to be managing flaky dev boards. (For those interested, we solved this for armv7 initially using Calxeda hardware, and later using aarch64 hardware running in 32 bit mode).