Orkz can go non mech for sure, A Green Tide army has a crap load of boyz mukk'n about! Start with your Warboss (Thraka) & 4 maxed out squads of 30 boyz (each with a Nob w/
PK &
BP) Your now at 121 models on the board! From there you can add practically anything to increase the size of the horde... a fully tricked out Nob squad (or 2), Lootas, Burnas, & Kommandos (w/ Snikrot) and ofcorse the awesome Big Mek (w/
KFF) are all awesome ways to grow your green tide!
Now going by your list posted, you do seem to have the start of a Kan Wall army, though you will need more boyz (get up to 90), a big mek (or 2)(w/
kff), 3 more kanz & some lootas to get the ball rolling nicely!
Oh and keep 3 of the Koptas (with buzzsaw's & twin linked rokkits)
Search around Dakka for some Green Tide & Kan Wall Lists for some inspiration!
Also... if you are liking the trukks & battlewagons... a Wagon Spam list can be fun to, they can be fast n dirty and will get you into the fight right away! Search for a few of those lists as well to get an idea!
As always, read the
BRB and your Codex to familiarize yourself with the rules & your army, see what can & can't be done with Da Orkz... trust me, you won't be dissapointed!
Most of all... have fun!