Lab80 and others
all the Lab turntables use essentially the same motor, platter and bearing.
I agree that idlers are jumping in price as more seem willing to try them.
My TT is a Sugden BD1 in a new plinth, and my "Nanook's $2.19 tonearm". Do a search, I've posted a bunch. of information and pictures. Even the re-plinth has been posted. I've changed the design slightly for ease of manufacturing, and am contemplating a major revision. I've retained belt drive, but use a tough knotted nylon thread as a belt.
The tubing is Easton (arrow shaft). This tubing is typically in the 70-90 ksi yield strength range, and is veery light. The headshell is a Yamamoto inspired one made by someone else. If it seems I'm being a little vague, I am. I am contemplating making a commercial version....but priced very modestly. Please note: this tubing is very brittle, and cannot be bent. Any changes to the shape of the arm have to accomplished by other means. I've changed the design slightly for ease of manufacturing, and am contemplating a major revision. The uni-pivot bearing is perhaps amongst the very best available at a very reasonable cost. Rather than spell out a recipe for the arm, I encourage you to PM me. This particular arm is 330mm in effective length, and is set up for 15mm O/H. Th picture shows a brutally crude arm rest, but that is being altered as well.
The issue with idlers is that now, anybody who has any idler (whether a good design or one in good condition) think they can get the same kind of prices as some of the best, more so than with any other type.
Often many good designs are ignored, because they do not have the "cache" of the big dogs. Dual (the brand) is in this situation. The idler Duals are less desirable than the Garrards, the Thorens, the Lencos, etc. They can be had for very little money. and can give years of great service. They also have a good bearing and a great bearing.
Attached is a picture of the arm, hopefully large enough to see some details., and another larger over-view of the table. The hard drive in my 20 inch iMac died this past week and I've lost everything, but as required, I've been taking photos...
Don't be discouraged.
My personal suggestion might be to consider a Dual idler in a custom and a "219" ( plinth

) arm.
All new arm parts can be had by me , fabricated and ready for assembly for a very modest fee. (Admins, I am not pandering any for sales, and as P10 and Cal can attest to, I have no desire to offend any. Please move this response to "Vendor's Bizarre" if deemed as inappropriate here).