Hi,
Believe it or not most toaster brands are designed to toast "uneven".
The concept behind it is to improve "buttering". You may find that some toasters have uneven heating elements (one heating element in the middle for both slices of bread).
Although many would say Dualit toasters are OTT for households, since they retail at £178.80 - I have had mine for 13 years and so far have not even had to replace the heating elements yet.
The heating elements can be purchased for around £18 direct from Dualit.
If you are after other brands of toaster it is worth looking at;
Villaware : Only a two slot toaster, however has an entirely removeable crumb tray (opposed to the slide out trays) and has controllable widths on your toaster slots.
Kitchenaid: Expensive, but they look very nice and robust. They are essentially two toasters combined to make a larger 4 slot toaster, I have had issues with 2-3 of my customer's where one side would stop working.
Bodum: Cheaper toasters, retail at £49. Thin Silicone covers the entire case to give that "soft-touch" feel.
Either way, as with computer components you get what you pay for, Russell Hobbs, Bosch, Breville etc. are cheaper brands but come with cheaper components and quite often cheaper guarantees.