You should be able to find several (ebay, audiogon, etc.), BUT:
1) Make sure they have original boxes/packaging
2) Find out if they have original or replacement panels. You can ask for the PANEL (as opposed to, but in addition to the speaker) serial #'s - there's a serial decoder on here somewhere that will tell you the age.
Depending on environmental factors (smoking, pets, "sea air", humidity, etc.), panels average lifespan seems to be 15-20 years, after which panel replacement is a real consideration.
If it's just a "toe-dipping", maybe look for some Aerius i's... you can find them for $500 - $1,000. Check with Martin Logan on replacement panel prices for them, and when you're done, you would have some decent, "like new" mid-size speakers for $2,000 - $2,500.
Also, consider bi-amping with Active Crossover (
https://www.martinloganowners.com/threads/how-to-active-bass-section.19237/)
The Active X-overtopic is covered for multiple ML speaker models on here... depending on how you like getting your hands dirty, you could leverage any on of the ideas/designs/component lists provided.
Have fun!