3D Viewer in JavaScripit/WebGL

I own and operate a small consulting operation in Cambridge, Massachusetts, USA, specializing in rapid development for local startups. For one such client, we have developed a 3D "CAD" style viewer using JavaScript and WebGL. The JavaScript code is well written and performs well. However, our client may want to engage us for future feature development, and the original author (who we had subcontracted) is not going to be available to perform the work (he will be available for consultation and to help our new subcontractor come up to speed, answer questions, etc.)

Normally we pay a flat fee to develop a specified set of (agreed-upon) features within a one-month sprint -- we try to get "feature complete" after three weeks, and use the final week to shake out any issues. You would need to be very proficient with WebGL, object-oriented JavaScript, and AJAX, and be comfortable using Subversion.

Are you available to take on a project like this? Any information about your availability, rates, and preferences (per-project, hourly...) would be appreciated!