One thing I am often asked is how much compensation a Sales Engineer should get. According to the Occupational Outlook Handbook, 2008-09 Edition in the US the middle 50% of Sales Engineers earned between $59,490 and $100,280 a year.
This description of SE is across all industries, wholesale and manufacturers. The median earnings of SEs in the computer systems design and related services industry was $90,950. Also, overall the top 10% of SEs earned more than $127,680 a year. Of course the earnings of SEs is highly variable and dependant on performance. Those doubling quota might find that more than half of their overall income comes from this performance based aspect.
While this is just the raw data from a major survey (over 76,000 people), it does help you work out where you sit. With such large ranges of course, it is important to know where you sit both in your organisation and across other businesses and industries.

While this is just the raw data from a major survey (over 76,000 people), it does help you work out where you sit. With such large ranges of course, it is important to know where you sit both in your organisation and across other businesses and industries.
Comments
I'll check back to see if anyone else is interested in the topic, and if so, share what my group does.
I have heard of anything from 10%-40% OTE (on target earnings) being performance based. It can also be calculated by any of the ways you mention. In short - I'll get back to you.
thanks