Those are pretty nice switches - I was looking at them recently as well. They are available with a variety of switch elements and appear to use an aluminum part into which (I assume) standard switches can be inserted. Here's a three position version available here:
https://www.ebay.com/itm/Handlebar-Grip-Headlight-Spot-Fog-Light-Indicator-On-Off-Switch-for-Motorcycle/172690079010?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649
Anyhow - the answer is 'yes'.
V3.0x firmware
Tie the switch from the AuxIn to Gnd if you want to control Presets. Presets allow you to change many settings at once. You can use this type of switch to control limits as well (such as Speed as you requested), but you will need a couple of resistors and fiddle with the AuxMin and AuxMax settings to get the voltages to match your desired limit percentages - kind of a PITA.
V3.1 beta firmware
The newer firmware makes this easy. Tie the switch from the AuxIn to Gnd to control either presets or limiting. Set AuxA to '2-pos sw' . Select either presets or Limiting. For Limit mode, fill in the the desired 'Low' switch percentage - the other position is 100% of the Max Limit configured for the parameter of interest (MaxCurrent, MaxSpeed, etc). So for Speed, select 'Speed Lim', set 'MaxSpeed' to be the 100% value for one switch position, and then the percentage of that in the 'Lo Level' setting for the speed at the other switch position. Easy peasy.
The 3.1 beta firmware also lets you use a two button up/down arrangement either alone or in conjunction with your switch (to control two things). The buttons can be configured for 2 to 32 levels.
Since you're asking, I'm guessing you have the 3.04 production firmware. Get a programming cable and flash the new 3.1 beta stuff - much cooler than the basics in the 3.0 production code.
Also - although you mention searching ES for hints, you should always go to a company website first and look for manuals. There you would have found a link to the
Unofficial Guide posted here on ES in the CA V3 Beta thread. The Guide describes how to wire the 2-position switch, etc. (see section
"5.6 Auxiliary Pot"). Subscribe to the CAV3 thread to get notifications when new firmware and features are released.
Anyhow, you have some options...