A classic Mathematics project! I've done this many times with students of all abilities. Easy to extend for those who need it - add in some elements like finding the costs of floor coverings, lighting, etc. Using specific 2D shapes for the different parts of the bedroom or overall shape of the bedroom allows for links to other parts of Numeracy.
This download includes a project sheet (3 to a page for reduced photocopying!) and a rubric. Both are easily customisable.
A fun activity that really engages!
Hope your students enjoy it as much as mine have!