I would go with bunks, but there are many, many configurations of BH models to choose from other than the quad bunk. Check out the floorplan like mine (KZ Spree 318BHS-although many manufacturers make this plan too); Forest River (and others) make a great plan which has a 3 bunk configuration with an extra table in the back as well; and given that you have an Excursion, check out the Heartland 32BHDS (or the Keystone Bullet 295BHS in a lighter unit) which has the ultimate kids' suite in the back.
Thanks for all of the feedback. After reading all of the great replies and surfing floor plans on the web for a few hours I think we have decided to go with a bunkhouse model. We are not real keen on using the dinette and/or couch for beds as we do not want to have to make up and put away beds daily. Our little guys would be fine on the floor soon but I'm sure as they get a little older they will want there own spot in the trailer. With our current HTT the wife and I each sleep with one of the boys in the end separate end bunks, not the best sleeping arrangement but it keeps the little guys from ending up on the floor at night. We tried them on the floor and they are more interested in playing then sleeping :-) I'm going to try and look at a few new trailers after work this week but will probably hold of on the final decision until the RV shows come to town in the next couple of months.
Bunks. They sure made my life easier. Beats making the beds up all the time or setting the tent up each time. Had a hybrid before. Now a bunkhouse. No wet tent ends or wet tent to put away if it rains. Camping is suppose to be fun, not labor intensive for me. I have two boys and the Crossroads ST30BH. Love it. Life is good.
I didn't read all these posts, but I'll put my 2 cents in for bunks. Your kids are young enough that you'll get lots of use out of them. You'll be good until they get to be about 13/14 years at which time it can be awkward (depending on design) for an adolescent to get in and out of a top bunk. That is our experience, and I'd do bunks again if I had to do it over.
I'm a huge fan of the bunk house models and we are on our second one. We have three girls that now are 12, 15 and 17 and most of the time we still ave all three of them with us when we camp.
They love the bunk room so they have some privacy and their own TV/DVD player in there. They can go to bed when they want and get up when they want and not be in anyone's way.
Having the sofa and the dinette available at all times was important to us. Sometimes we are up late or get up early and we just like to have that space available when we want to use it.
Every once in a great while they want to try a tent... that usually only lasts for one night then they are back in the bunk house!
We have 4 kids (7,6,4,2) and had a 3 bunk hybrid for 2 years. Moved up from a PUP and the the packing and fact that we didn't have to make the table into a bed every night were priceless. But...after all our trips (see my signature) the fighting over having to share a bed, the fact that the 7 year old wants to read and the 2 year old needs to go to sleep, the 4 year old sleeps with more stuffed animals than you can count, and the 6 year old just wants her own space they needed their own space.
We bought a 4 bunk model a few weeks ago and have had the opportunity to use it once so far and it was wonderful. Each of the kids have their own space and bed time was wonderful. Our kids a little older than yours - but one day your kids will be this old. When we were shopping for the trailer the first things my kids noticed and were quick to point out was whether they all had their own window and whether they all had their own light. Just something to think about for the future.
Also remember to look at storage for their clothes. The small clothes you have now are going to get bigger. Not all the bunk house models seem to have adequate storage for the clothes where they could access them on their own as they get more independent. You may be able to put a suitcase in their bunk now but the taller they get, that won't fly either.
Went from a Hybrid to a quad bunkhouse- our 3 kids love their own room and no fighting over who sleeps where, shares a bed, folding down sofas or dinettes. You have an excellent tow vehicle so you should have LOTS of available choices.