It wasn't long before I got in over my head when I attempted to renew the oil seals on the K1100LT forks. 
I removed the bolt on the bottom of the slider, which presumably frees the cartridge/rod/spring assembly.  When I pull the slider from the tube, it stops suddenly with a metallic clank.  It's not clear what is preventing the two pieces from separating, but I'm not optimistic that this will end well.
Any ideas of what my next step should be?

This is often a problem when dismantling the Marzocchi forks.
What's happening is that the lower internal bronze bushing spreads out
and hooks the upper bronze bushing.

Have a look at this link:
https://www.k100-forum.com/t2499-k100rs-front-fork-stuck-replacing-oil-seal#20147

It's recommended that you mount the new seals from the top of the stanchions.

Thank you for pointing me to that thread, Inge.  I see I'm not the only one to have this problem.  I'm disappointed that Marzocchi forks on a top tier motorcycle would be so troublesome after a mere 22K miles of use. 
Well, no point in grousing about that questionable design.  What I need to do is solve the problem.  At least one other owner has used brute force to separate the stanchion from the slider, so I'll attempt that.  I'll be glad to destroy the seals/bushes if I can avoid buying a new slider....
Race Tech, an aftermarket suspension supplier, offers bushes.  Does anyone have an idea if they would be superior to the BMW OEM bits?  Race Tech promotes their product as very low friction, which appeals to me. They are probably more reasonably priced, as well.  (edit: BMW wants about $165 US for the bushes!)
I'll certain install all oil seals by sliding them down from the top of the fork tube in the future.