You are not being unreasonable, because it pretty much is unreasonable to get a dog when you are both working full time..
HOWEVER..
If you can afford dog daycare or dog walker daily.
If you are willing to make compromises in whatdog/how many dog/how old dog..
A pair of greyhounds who have been kennelled together years (not just slung together by a rescue!), direct from the trainer off the track...
Who arrive with you when you have a fortnight off work followed by your OH having a fortnight off HIS work... followed by doggy daycare/petsitter/dog walker as dogs needs dictate...
Could work out well for you - but not cheap, and maybe you don't want a pair of greyhounds, who will be (and this is the reason it would work) institutionalised and mentally deprived (sorry greyhound fans but thats the truth, they are!) and possibly thus always remain a bit 'thick'...
They will almost always come needing to be taken to the vets requiring a dental and any lumps/bumps removed/spayed so you'd have to factor that in.
People can do it and can make it work IF they are willing to make the sacrifices and compromises needed.
A pair of greyhounds who have only ever known van - track - kennel - dog box and paddock will be in the lap of luxury with a whole house, people to cuddle at least 12 hours of the day, each other and regular walks/toilet trips.
But they will also need educating as to waht a washing machine is and what a non-greyhound shaped dog is and what a ROAD is and.. basically everything that is not van - track - kennel - dog box.
As pp's have mentioned it is also hard to find rental properties that accept dogs and ones that accept two large dogs, even harder.
The reality is, you'd be spending a LOT of money as well as time, to make this work - you would have to want it really, VERY badly indeed.