Hi,
At First, ABAP is a proprietary language of SAP used only with there systems (a limitation).
As far as getting good paying ABAP developer job immediately after completion of ABAP course is rare, as most of jobs advertised require good command on ABAP and substantial work exp. of ABAP. This holds good for even SAP certified institutes like Seimens. But yes once you have 2-4 yrs of exp. SAP professionals are in very high demand as it is a market leader of its segment with around 55% market share and continues to strengthen its position there. Else, if one can show some fake ABAP experience on resume to get a job, but recently it has started becoming risky as more and more companies are going for background check.
Moreover, as earlier pointed out do not fell in trap of institutes that provide job guarantee, they can only arrange for interviews with small companies (only adds to frustration). The best place to learn ABAP is on job as you gain experience along with it.
Since you already have some experience of domain, why do not you try a module specific SAP training like MM, FICO etc. Basic ABAP can be learnt from SAM's 21 days book; I think it carries evaluation version of ABAP also. A SAP package will help more as you have domain exp. with ability to write code for it.
Aditya