If I abandon a slow to verify transaction is my wallet recredited?
To understand the situation fully, let me clarify what happens when you publish a transaction.

Upon publishing a transaction, the bitcoins do not "leave your wallet". At any given moment, a "bitcoin" exists as an address in the blockchain that has an "unspent output". Publishing a transaction simply broadcasts your intent to spend that output to a new bitcoin address, but until the transaction is confirmed (mined into a new block), your bitcoins still reside at their old address.

So, after publishing a transaction, the network's nodes will understand that someone is trying to spend an unspent output, so your wallet will not give you the ability to spend those coins more than once (there are some special cases, but for normal transactions this is the case). So it appears your coins are unspendable, locked 'in limbo', but they in fact still reside in your address, until the transaction confirms. 

You can make your wallet forget about its previous unconfirmed transaction, but you will never be able to guarantee every node in the network will also forget it. If your transactoin does not confirm after a long while, enough nodes will likely forgot the transaction that you will be able to publish a new transaction to re-spend the coins. 

So bitcoins cannot become 'lost in limbo', there just might be times where the network ignores a more recent transaction, in favour of another older one that that spends the same coins, and that they saw first.