RCA Digital Cable Rec's under $75

If you win an auction for Auricle Audio Design's Encore Signature Digital interconnect then you can probably request an increase from standard length up to your needed 2M.
Performance that has to be heard to be believed, at a less than reasonable price.
You can email through the Audiogon system to fellow member Joemazzaglia, and see if he has time to squeeze in your special need order.
This digital IC comes from a dedicated audiophile who actually designed a unique RCA connector he crafts by hand for each end of the IC.
Adds zero jitter to the digital signal sent from the transport (as measured by the input readout on my Genesis Digital Lens) as the signal is forwarded to the DAC.
By the way, sending your DAT analog output to a preamp would use an analog IC design, the Encore KA analog IC. Another high end performer for the very budget conscious, or those who buy by ear, not by how much lighter the wallet will feel.

As you probably know, the challenge is going to be finding anything used in that length. For the money you have, I would up the ante a few bucks and get a VH Audio Pulsar new for $113. This is a highly regarded piece - meaning lots of people have bought them and are pleased, Chris Venhaus stands behind the product and offers exceptional service and support, and there is a ready resale market for them here on AGon.

Certainly Signal Cable makes fine cables, as does Apogee.

You could also work the auctions on AGon - a BMC Pinnacle (Black Mountain Cable) is coming up today