As promised, here is a Cliff's Notes version of the law of quantum meruit in 
the State of Texas.

The doctrine of quantum meruit is based on the principle of equity that a 
party deserves to be paid for the services or materials he furnishes to one 
who knowingly accepts them. See Davidson v. Clearman, 391 S .W.2d 48 
(Tex.1965). This remedy is based on the promise implied by law to pay for 
beneficial services rendered and accepted. Id.; see Campbell v. Northwestern 
Nat'l Life Ins. Co., 573 S.W.2d 496, 498 (Tex.1978). The Texas Supreme Court 
in Bashara v. Baptist Mem'l Hosp. Sys., 685 S.W.2d 307 (Tex.1985), set out 
four elements for recovery under quantum meruit: (1) valuable services 
rendered or materials furnished; (2) for the person sought to be charged; (3) 
which were accepted by the person sought to be charged and were used and 
enjoyed by him; (4) under such circumstances that he would reasonably know 
that the plaintiff expected to be paid for the services. Bashara v. Baptist 
Mem'l Hosp. Sys., 685 S.W.2d at 310 (quoting City of Ingleside v. Stewart, 
554 S.W.2d 939, 943 (Tex.Civ.App.--Corpus Christi 1977, writ ref'd n.r.e.)).

There are several cases -- all outside the State of Texas -- in which 
recruiting agencies seek recovery under the doctrine of quantum meruit from 
companies with whom they have placed an individual.  Cutting to the chase, 
the fundamental inquiry in such a case -- have the elements of quantum meruit 
been satisfied? -- ends up being a factual issue for a jury to decide, not a 
legal question for a judge.

Let me know if I can be of further assistance.