A bit unexpected, but 10G is back as a real low-cost solution.
48x10G + 6x40G Netberg Aurora 420 with x86 CPU and ICOS NOS and Broadcom Trident 2 BCM56854 ASIC is available just at USD 4000.
A brand-new, fully-functional 10G L3 switch with Linux shell tools, covered by 3-year warranty with a feature-rich software stack was never that low.