All wholesale income falls into ordinary and is subject to income tax.

Can anyone recommend a title company or closing attorney in Maryland that does subject to? 

We had one seller turn us down with expletives then went through hoops to comply with higher offers subject to conv., financing only to be denied regardless of work done.

Nothing could be further from the truth.I stand by my point that there are multiple ways to do SEO correctly and especially by avoiding black and grey hat techniques.I appreciate the good debate on the subject.

What subject you like? 

So lets say I get a property under contract to purchase subject to the existing mortgage.

If you must invest out of state, I would recommend getting multiple opinions on the subject property (property manager, contractor, agent, etc.).

Possession of the Property and Inclusions will be delivered to Buyer on Possession Date at Possession Time, subject to the Leases as set forth in § 10.6.1.1. and, if applicable, any Post-Closing Occupancy Agreement.

Does anyone have recommendations on subject-to books or resources?

It is rental income from the subject property that you're buying that can be counted as income.