This is build for moving y bed Cartesian type 3d printer using all parts from Openbuilds. The assembly was rendered with 300mm length but can be scaled to whatever length you need.  the bed is using Xlarge gantry plate which is the right size of things I print 95% of the time. There are two plate sandwiched on top of each other. the top one can be secured with M5 screwed and unscrew to make the bed removable. 

[Update 1]  Added BOM with link below and uploaded PDF drawing

BOM mostly from Openbuilds:

- (x1) http://openbuildspartstore.com... (300mm) 

- (x1) http://openbuildspartstore.com... 

- (x10) http://openbuildspartstore.com... (M5x20) 

- (x4) http://openbuildspartstore.com... (M5x25) 

- (x4) http://openbuildspartstore.com... (M5x8) 

- (x4) http://openbuildspartstore.com... 

- (x2) http://openbuildspartstore.com... (6mm) 

- (x2) http://openbuildspartstore.com... (6mm) 

- (x3) http://openbuildspartstore.com... (need about 760mm) 

- (x1) http://openbuildspartstore.com... 

- (x1) http://openbuildspartstore.com... 

- (x2) http://openbuildspartstore.com... 

- (x2) http://openbuildspartstore.com... 

- (x1) http://openbuildspartstore.com... 

- (x1) http://www.printinz.com/printi... (125mm x 125mm)