Dave Smith Instruments Prophet '08

Inspired by Matt Hunsberger's Akai AX60 and other synthesizer drawings, I decided to take a shot at illustrating the Prophet '08 in Photoshop. This is what I have so far.

All elements are rendered in photoshop as gradients, patterns, etc. except the wood siding, which I sampled from a texture gallery. More about this synthesizer and the image I used for tracing at: http://www.davesmithinstruments.com/products/p8pe/p8pe_photos.php

The main problem I have run into is that it is too finely detailed to easily resize. Any tips for preserving the hard edges of the lines (keys, outlines, shapes, etc.) when downsizing – without redrawing or pixel-nudging each element?