I've been working on it for my home campaign.
I bought Spycraft when i came out, and I bought d20Modern also. I've always wanted to start a Modern Era Spy campaign and have always intended to use something from both systems.
My campaign has been running for a couple weeks now, and I found it extremely EASY to use d20M for almost everything. In fact I've been basing the campaign on Top Secret SI. Since I own most of the material, I've found it extremely easy to convert on the fly. TSSI was based on a % system that converts easily, as easy as dividing by 5. Removing any FX related classes, feats & skills is easy because it's not included in any of the Default rules [all the FX feats are found only in the Campaign Model chapters.]
But I haven't put my Spycraft book to waste. In fact the Chase system and Gadget systems are usable with almost NO conversion. The vehicle stats are almost equivalent across the board, as long as you are consistent and use just d20M numbers. Maneuvers that are Daredevil Only were easy to convert too. You must have a level in the Daredevil Advanced Class. I also found that Gadget system, which is essentially a Requisition system works perfectly as-is, since gadgets are uncommon "trade tools" they work along side the d20M Requisition System. I also give the characters 3 gadget points for permanent vehicles, and I'll add another point every other level or so. Another reason I chose the d20M system, is that the characters don't have the be Spies forever. and I can easily slip in some FX later on, if I want to sneak in some occult or supernatural events. [hehe, shhh, don't tell my players.]
Basically, I've found d20m easily adaptable to a non-FX enabled campaign with spies.
I'm wondering if anyone out there has consolidated the Spycraft Gadgets (and Vehicle Gadgets) onto dandy handout. I'm ready to do it for personal use, just wondering if someone else has already done it.