Sorry, I've been out for awhile since I had an extremely bad reaction to some medication. Only just starting to recover but I'll work during the weekend to make up for it.
Today, I spent awhile looking at possible current drivers online. Dmass said that the Thorlabs one is not being used for any frequency sensitive measurements. After looking online, nothing seems to beat the Thorlabs driver in terms of noise level (<1 uA RMS), so maybe we will need to look into building our own current driver or buying the one online based on Libbrecht and Hall. That one is quoted at $4000-5000.
I also spent awhile trying to figure out a new box design. I think we will want to purchase an AR coated window for the output beam, much like Birmingham. 1" diameter should be sufficient based on the size of the diode/collimator lens. Thorlabs and Newport have comparable products with regards to this (http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1117). It is also important that the box is airtight so no dust can accumulate on the grating or diode. I was thinking of having a 2 part box, with the metal folded, but I'm not sure how easily the machine shop can do this (fold thicker metal sheets, create rounded edges). Waiting to hear back from Tara about this.