I think there are many studies to support short implants. Deporter, fugazzatto, toffler, etc just to name a few.

I think case selection is critical.

Read this article it may change your view.

Abstract
Journal of Periodontology
2009, Vol. 80, No. 11, Pages 1700-1718 , DOI 10.1902/jop.2009.090107
(doi:10.1902/jop.2009.090107)

A Systematic Review and Meta-Analysis on the Effect of Implant Length on the Survival of Rough-Surface Dental Implants

Sotirios Kotsovilis,* Ioannis Fourmousis,† Ioannis K. Karoussis,† and Christina Bamia‡
*Private practice, Athens, Greece.

†Department of Periodontology, School of Dentistry, University of Athens, Athens, Greece.

‡Department of Hygiene, Epidemiology and Medical Statistics, Medical School, University of Athens.

Correspondence: Dr. Ioannis Fourmousis, Department of Periodontology, School of Dentistry, University of Athens, Thivon St. 2, GR 11527, Athens, Greece. Fax: 30-210-7461202; e-mail: yiannis@fourmousis.gr.
Background: A meta-analysis on the survival of short implants compared to conventional implants has never been performed. Therefore, the aim of this study was to address the focused question “Is there a significant difference in survival between short (≤8 or <10 mm) and conventional (≥10 mm) rough-surface dental implants placed in 1) totally or 2) partially edentulous patients?” by conducting a systematic review and meta-analysis of prospective studies published in the dental literature in the English language up to and including August 2007.

Methods: PubMed and the Cochrane Central Register of Controlled Trials (CENTRAL) databases were scanned electronically, and seven journals were searched manually. In the first phase of selection, titles and abstracts, and in the second phase, full texts, were evaluated autonomously and in duplicate by two reviewers. Extensive contact with authors was carried out in search of missing, unclear, or unpublished data.

Results: The electronic and manual search provided, respectively, 1,056 and 14,417 titles and abstracts. In the second phase of selection, the complete text of 300 articles was examined, and 37 articles reporting on 22 patient cohorts were selected. Meta-analyses revealed no statistically significant difference in survival between short (≤8 or <10 mm) and conventional (≥10 mm) rough-surface implants placed in totally or partially edentulous patients.

Conclusions: Within the limitations of this systematic review, the placement of short rough-surface implants is not a less efficacious treatment modality compared to the placement of conventional rough-surface implants for the replacement of missing teeth in either totally or partially edentulous patients.

I have seen more failures with short 9mm or less then with long. I would say if your not comfortable doing a sinus lift refer to get it done and then place a longer implant.

My opinion.