I can fully understand you. We have the same problem. Didn’t find any suitable base cabinets and thought we’d either make something ourselves or buy some nice ones elsewhere. The problem now is that the 2 sinks, in terms of width and spacing, are not standard. For example, if we took 2 base cabinets of 80 cm each, the cutout at the back of the cabinet for the siphon wouldn’t fit properly. And you don’t want a 2 cm gap between the two cabinets either. And a large continuous cabinet under 2 sinks doesn’t work either because the cutout for the siphon is always fixed and then doesn’t match the width of the sinks. So we went to a carpenter and obtained several quotes. The cheapest was €2,600... for a base cabinet about 170 cm wide with 2 drawers... for that, I could have had a very chic one installed through the general contractor. We actually regret that at the moment. And we still don’t have a cabinet :-/ How is it with the Ikea cabinets? There is already a cutout for the siphon in the middle of the cabinet, right? If the back is completely open, maybe you can really craft something nice there.
I just tried to find out. Regarding the IKEA Godmorgon cabinets, I can’t say whether they have a cutout for the siphon or if the back is completely open. From the photos and illustrations in the assembly instructions, I would assume that the top drawer is generally shorter. But the website is a nightmare, and I can’t find anywhere how deep the drawers are. I think many people here in the forum use them, maybe someone with practical experience can help us out. The deeper Godmorgon cabinets come in widths of 80, 100, and 120 cm, so you could definitely make something work. Possibly complemented with above-counter sinks. I think you can certainly run the hoses for the angle valves even if you have to bridge a bit more distance. The siphon situation would need to be checked. But there are also versions that are longer/flatter. I’ve seen that before. If necessary, ask at the hardware store. I personally don’t like the countertops for the IKEA washstands at all, but basically you can put anything on there (kitchen worktop, wooden board from the carpenter / cut to size, we bought ours made-to-measure on eBay). Or you take one of the built-in sinks from IKEA if you can come around to them.
Which Ikea cabinet do you want to put underneath? Or hang? Wouldn’t it be nicer if this countertop hung freely on the wall? There are these brackets where you can also hang a towel over the bar. Or else have something made from steel runners and place it, which is really cheap and widely available. If the Ikea cabinet is narrower than the countertop, then these are usually open on top as far as I know. Basically, you can also hang kitchen wall cabinets from Ikea under the countertop or one/two Metod drawer cabinets or the Godmorgon... in gray and wide, it’s very nice. For this beautiful sink, though, you have to ask exactly which drain fits or ask the manufacturer.
We want to mount the narrow Godmorgon cabinet underneath. Hanging it freely on the wall wouldn’t be my thing. I know that’s trendy right now, but I don’t like the open view of a siphon, even if it was a stylish siphon. I prefer it with a cabinet around it. I had already thought about Metod, but even the narrow version with 37 cm is too deep for our bathroom. The Godmorgon is only 32 cm. The countertop is also finished to fit that. The sink has a standard 45 mm drain. I think (hopefully) I can use just about any. I’m skeptical, but so far every sink always listed 4.5 cm.