I had posted about an oil pressure guage put together from the parts bin just for checking pressure while doing 3K mile service stuff. If you track that thread down and check the pix, the description below might make a little more sense.
Based on that exercise, it would be fairly easy to assemble something that would place a small gauge down where the sender unit is. Wouldn't give you a dash readout, but would be handy enough to stop and get off the bike to sight the gauge when ever curious. If you positioned the gauge like the tester I made, you could look down while riding to check it. The tee I describe would preserve the idiot light function on the dash.
The simplest way to me to visualize the set up would be working from the crankcase outward:
Install a M10 X 1/8 NPT adapter (available in a set of different sizes from Autozone) in the hole normally occupied by the sender for the idiot light.
Use 1/8 NPT nipple to install a 1/8 X 1/8 X 1/8 NPT tee to the adapter. Use one of those flat sided ones that looks like "billet brass" instead of the regular plumbing types that look like you robbed it off of a gas heater supply line. Have the long dimension of the tee vertical and tighten it so that the middle or side opening faces either forward or at right angle to bike's centerline
Find and install a small liquid approved gauge 0-100 psi range in either the side or top hole of the tee. 1" diameter gauge with 1/8 NPT fitting on the back would be good. If you can't find that size or a back mount style gauge, you can play with low mount gauges of whatever size will clear everything.
Instead of the stock sender, pick up a sender from NAPA with 1/8 NPT threads for American engines. You should be able to get it in the specific pressure you want the light to come on at - ie., 2psi, 5psi, 10psi or whatever. Put this sender in the remaining hole of the tee.
Disclaimer: This is a mental exercise, and I haven't actually put this together yet. YMMV depending on parts availability and your aesthetic sensibilities arranging the pieces
If I ever see a good accurate gauge either 3/4 or 1" diameter in that psi range, I may try it. If you do a lot of track days, the tee and associated bits may be too risky for breakage in a crash - and at the pressures these motors pump oil, you could oil a lot of track before the motor stops turning.
As I proofread this, I thought about going the extra mile and having a good Ducati logo engraved in relief on the flat sides of the tee to really throw the detail freaks 8)