The main issue is not the price, it's the delivery time that takes long
We need to perform the installation sort of asap. we'll be able to seperate the new cluster from the shared switches to the new dedicated ones if there will be but it could take a few weeks, in the meantime the switches will have to be shared
Sharing cluster switches is not supported or supportable, sorry.
I would suggest to setup as a 2 node switchless cluster, then expand to 4 nodes when you get the additional switches
In 9.3 we remove the ability to specify the name of the cluster you wish to join, so you'd have to monkey around with manual vlan configuration etc (and ideally a second set of links between switches). Not the way I'd want to run my enterprise storage system..