A bog standard under the roof cupboard that looks absolutely average - you got to be kidding me...
PAX will have been perfect for this, although judging by the height might have even gone down market with PLATSA - for the doors you can either add mirrors or buy already pre-made mirror doors online. Re-use the IKEA hinges and voila... IKEA particule boards are ideal to cut to size - what do you think the people who built your closet did? They take rectangular panels and cut them to shape.
So no - I maintain custom cupboards are a waste of money. But then again, I do developments in London and have margins to watch for, if you got the cash to spend why bother. Just like why bother trying to source cheap hardwood floorboards when you can just pick some for 4x the price.
So to OP - IKEA is a perfect option if you are working with anyone who has a basic idea of carpentry.
Here is an under the roof one - first google hits: IKEA PAX under the roof https://www.pinterest.ch/pin/2322237297266458/
https://www.google.com/search?q=unde...-uy8BE1MaSljjM
A cupboard like bossbaby would have taken me about 2 days to put together with IKEA and buying some bog standard mirror doors at LeroyMerlin or any other hardware shop, although am almost sure even IKEA has some, but I find mirrored door naff and prefer to buy this so as not to have any handles (I do like handles in some projects, depending on the space I am working with! In this case with the money saved you can splurge on something really out there!):
https://www.fobi.fr/loqueteau-pousse...netique-p59849
Thanks for the laugh though bossbaby. Just finished putting together another "custom" wardrobe this week with IKEA, tried to upload on the forum, but the forum is too old school to let me upload something that's more than 40kb. I'll be putting that project on houzz later this year and will link to it.
OP Don't be a snob, buy IKEA and you'll thank me for it later. Unless, you actually have something really out of the ordinary, read: 5 meter high cupboards with 25 cm width and you need golden shelves... Or if you have the cash, don't bother and pay a carpenter to do everything from A to Z, but then you wouldn't be on the forum in the first place asking for tips I expect?