As has been stated, ALL of the extremely high precision CMMs use fixed probes. The Renishaw indexing head is simply not repeatable enough for these machines to maintain their accuracy. It is said that 90% of the "typical" CMMs error is in the probing. I don't know if the high end machines can be considered typical.

Rhetorical Question #1 - how much precision do you require? If you need accuracy to a few millionths, you have no choice but to go with Zeiss, B&S Wetzlar (formerly Leitz), SIP, or equivalent, all of which will have the fixed head. There are still differences, but at least one issue would be off the table. And, as has been said before, bring your checkbook.

I think it is safe to say All CMM manufacturers support scanning of some sort. This may include touch trigger probe and/or hard probe. A general rule of thumb for touch trigger probes is a point a second. I've heard as high as 8/second. Hard probes can take data much more rapidly, but are mostly used on manual machines (e.g the Faro suggested previously, although again most OEMs offer manual machines).

A smaller number of OEMs support the SP600, laser heads, and the like. These probes can generate much more data in the same amount of time (on the order of hard probes), can be mounted to indexing probe heads, and can improve accuracy above touch trigger levels (but still not to high end levels). This support costs a little more, but no where near the high end machines.

Rhetorical question #2 - how much data is sufficient? The book is still out on this one! In fact, I know one user of an SP600 who is able to generate more data than their CAD system can handle! In any case, you may find that the trade-off between accuracy, time, amount of data, and cost completely justifies scanning with a standard touch trigger probe.