I finally seem to have come across a viable alternative to autocad for linux. Its called bricscad and seems to be much much faster in linux/ubuntu. I have given it to some other people for evaluation purposes but it looks to finally help engg companies and technically minded people to now switch over more easily to linux. Its not free but still much affordable.--they say its one 15th the cost of autocad.
Only Tally remains a barrier for the switchover from windows to linux for the general user at the small business office now--hopefully some alternative software for linux will soon come out so as to make the transition painless.
Kussh