Is there a way thru plugin or script to have more action centers in 3dmax similar to modo? When modelling I sometimes want to scale, rotate, etc from a given action center in object or subobject mode. Max is a bit limited in this respect where modo has so many action center you can pick from including from mouse cursor. Thanks.

You can scale/rotate about/around any arbitrary point.
Select the Tool | View (coordinate drop-down list) | Use Selection Centre (or Use Transform Coordinate Centre) from the Transform flyout.
Turn on Snaps (with an appropriate snap-type).
Select the object (or sub-objects) and lock the selection - this isn’t mandatory but you’ll find you keep accidentally selecting other objects / sub-objects if you don’t.
Select the axis/axes then (with the cursor snapped to an appropriate point) click&drag to perform the operation.

Max 4.2 through 2012 (SP2+SAP).
XP-64 (SP2)
NVidia 9800GTX-512 (Driver 266.58).
Core 2 Quad Q6600 2.4GHz, 8Gb Ram, DX9.0c.

You might also want to take a look into Working Pivots.  It’s a Pivot point that you can move to any arbitrary position to scale and rotate.

3DS Max 7, 8, 2010
Windows Vista 32 bit.
Intel Quad Core

Working Pivots require Max 2008 or newer and we don’t know which version geo_n is using.

@geo_n:- Please put your Max version (and brief system specs) in your sig - helps prevent any confusion arising from the differences between Max versions.

Max 4.2 through 2012 (SP2+SAP).
XP-64 (SP2)
NVidia 9800GTX-512 (Driver 266.58).
Core 2 Quad Q6600 2.4GHz, 8Gb Ram, DX9.0c.