Also Mifsuds currently have a 1dsmk1 for 599 (with 93thou activations - on average the shutters in these were good for 150,000 and costs about £220 to replace, a point to watch with your cheapy if activations are vey high or unknown) also make sure you get a charger as canon chargers for the 1D series are very expensive
and in answer to your general questions the 1DS is heavier than the 5D but better built - also it has a faster FPS rating
I think that the Mifsuds option is a reasonable price though I doubt they will be offering a warranty of more than 3-6 months and so I'd be inclined to take a look at the one the OP has seen. At £399 even if the shutter were to fail after 6 months the total price for the camera including a brand new shutter would still only come out to £20 over the Mifsud one.
The frame rates/sec of the 5D MkI and 1Ds MkI are almost identical at 3 and 3.3 respectively so you're only going to be seeing 1 additional shot over a 3 second burst. I do agree though that the 1Ds is both heavier and better built. I also find that the integrated grip is a much better fit in the hand than any of the add on ones offered for Canon's prosumer range of cameras, making the additional weight less noticeable. I'd sooner hold a 1D body all day than a 5D with battery grip
I'd stay with the later technology..., but isn't the 5D and the Mk1 the same era?
The 5D was released a month after the 1DsII, which both use the DigicII processor though in truth there's very little difference between them and the original 1Ds. It's only really at highest ISO settings that it shows in my opinion.
Thanks for the advice everyone, I think I will probably give it a go. Is there still a market for these though if I decide to resell? I only found 1 of these on eBay.
I would certainly take a CF card and if necessary a lens to the seller and ask to take a few test shots with the camera before commiting. When you get back home check the shots using a program called 1Dcount which will enable to you check the number of actuations for yourself.
That shouldn't be used as any sort of guarantee that if it says 100k you can expect to get another 50k before it fails, simply that if it said 240k like Mark's above I would make sure I had the funds put by for a replacement
I think it's fair to say that there's still a market for them. As for why there's so few up for sale? I'd like to think it's a reflection of the fact that most owners like the fact that they have a full frame, pro body with full weather sealing that still performs very well and so represents better value for money than the more expensive 5D.
