If they need to save the about two dollars it would cost to put the whole top on a box I would seriously question the rest of their quality. The frameless boxes I build are 3/4" all around. I use formaldehyde-free materials and they are glued and doweled together. Given your name this is something I would think you would require.

I'm curious what manufactures did you look at that were offering solid tops? It isn't common with frameless nor have I seen it often in face frame cabinetry. As it happens the company my Mom went with does solid tops but the installer told me neither Thomasville (Diamond) nor Kraftmaid do and almost all specs I have seen for cabinet lines show corner braces or side rails not solid tops.

Only cabinet that came without a top was the sink base. This company does all tongue and groove joinery right from this stock line they make for HD Canada to their custom line. It makes the cabinets really strong but it isn't necessary to build a quality cabinet.

My Crown Point cabinets came with solid tops. I'm very grateful for them because I've gone for 2 months without a countertop for my island but have still been able to use it because it's completely enclosed except for the one sink base. The Kraftmaid cabinets I used in my bathroom did not have tops.

My cabs don't have solid tops and they're quite capable of holding up my (very heavy) Richlite counters. I don't think I've ever seen (much less owned) cabs with solid tops.

jd - "If they need to save the about two dollars it would cost to put the whole top on a box I would seriously question the rest of their quality"

This downright insane. The extra wood there is not strengthening the cabinet in an appreciable way. It does nothing to help the compressive strength of the cabinet that help carry loads of stone or concrete countertops.

It looks spiffy and will help keep jobsite dust out of the cabinets (if you choose to install in a dirty environment) , but lack of a solid top IS NO INDICATION of quality of a cabinet's construction. It could be used as a marketing tool to differentiate you from competitors.

The really rich part is that it's a waste of material. It also adds to the weight and shipping and handling costs, so........not very green or organic afterall.

Thanks to all who responded. I was torn between Hanssem and Apple Valley (little more expensive). My question was because of information and drawings I found on the internet on the subject of frameless cabinetry -- they always show frameless as a complete box with drawers/doors in front. So I wanted to make sure the open top construction would hold up a granite/silestone countertop. No cabinet box will be wider than 30" so I think I'll be comfortable with the open top construction. Again, thanks to all.

organicsue you saw line drawings on the internet with solid tops, and now look at the great discussion you generated!
What is strong enough "to hold a solid surface countertop" is the side panel.
Sides, secured as mentioned above: "... attached to a wall in back and cabinets on both sides..."
I'm thinking about removing the solid base.
Then, I get more volume in my lower drawer (screwed into hole 23 in Ikea bases) and I'll be able to open the drawer with my foot.