I see a lot of talk about tuning the bands, what about those Marlins which don't use bands, any tricks for them?

Yeh,
the ones that dont have barrel bands probably dont need their bands tuned :p

Seriously,
there is an article in the tech section of this forum that covers accurising your rifle. From memory it covers both, carbines with barrel bands and rifles without barrel bands. I also recall reading another article on accurizing and think it may be on Paco Kelly's site.
Do a google on "accurising lever actions"

Basically the jist of these articles is that anything that stops your barrel expanding and contracting unhindered and anything that stops the barrels natural vibration, will have an effect on accuracy and needs to be alleviated.

I received this from a fellow at Marlin:

ACCURACY TUNING
A lot of accuracy problems in a lever gun can be traced to the interacting fits of the mag tube, mag tube tenon,forearm tenon and forearm.
If the fits have a lot of interference, and are difficult to assemble, accuracy WILL be adversely affected.
The tenons should be fitted to the barrel only tight enough to allow a "press fit" by hand. The mag tube should drop over the tenon stud easily and allow a little fore/aft play, say .010/.015". Trim the rear of the mag tube to achieve this type of fit if necessary.
The forearm should fit in the receiver and lay flat, in position on the barrel without any undue added pressure, trim the wood carefully at the rear of the forearm to achieve this type of fit. DO NOT TRIM TOO MUCH,OR YOU WILL HAVE A LOOSE FITTING FOREARM, NEEDING SHIMS!
The forend cap should fit to align the screw holes properly, trim the wood on the front forearm to achieve a proper fit if necessary.
These problems encountered in this area are due to a host of machining tolerances (which are all held "in gage") and swelling in the wood after manufacturing caused by humidity conditions

Thanks, that all sounds reasonable and simple enough.